What is VRRP in a Managed Switch?

Without VRRP (Virtual Router Redundancy Protocol), a router becomes a single point of failure in a network with a statically configured default route. VRRP is a feature allowing a LAN with a failed default router to use another router as a replacement.

With VRRP a virtual IP address is specified as the default LAN gateway. The address is shared among the LAN routers, one being set as the master router, others as backups. When the master router is unavailable, one of the backups becomes the master. When the unavailable master become available again, it immediately, automatically returns to being the master.

VRRP improves on dynamic routing protocols such as RIP and OSPF in that it recovers more quickly from a failure.

Protocol details are described in http://www.ietf.org/rfc/rfc3768.txt.

N101510.asp Aug. 11, 2005